THIS invention relates to a rotary distribution apparatus and more particularly, but not exclusively, to a rotary distribution apparatus suitable for use in a sugar refinement process.
In many processes it is necessary sequentially to connect different feed conduits and discharge conduits to process chambers of equipment. One typical approach is to use a plurality of conduits and valves to achieve the desired flow distribution between the various chambers. However, as the numbers of feed and discharge conduits and/or the number of process chambers are increased, the use of conventional piping and valves becomes cumbersome due to complexity, space and cost considerations. Although the number of valves may be reduced, through the use of multi-port valves at each process chamber, the complexities of the piping arrangement remains.
An alternative manner in which the above process requirements can be achieved is by utilizing a rotary distribution apparatus, as disclosed in the Applicant's prior patent. WO2004/029490 entitled “Rotary Distribution Apparatus”, the content of which is incorporated herein by reference. Further refinements and variations of such rotary distribution apparatus is also disclosed in the Applicant's patents WO2007/031857 entitled “Indexing Arrangement”, and WO2009/127978 entitled “Rotary Distribution Apparatus Incorporating Interstage Pumps”, the contents of which is also incorporated herein by reference.
One embodiment of an existing rotary distribution apparatus, which has applications in continuous ion-exchange, adsorption and chromatographic separation processes, is shown in FIG. 1. The apparatus has a stationary, cylindrical central core 1 into which fixed feed and product pipes 2 extend. A set of annular fluid distribution chambers 3 are defined between the core 1 and an outer barrel (or shell) 4 which rotates around the core with, in practice, one distribution chamber per feed or product stream. Pipes 5 which rotate with the barrel 4 are connected between selected distribution chambers and selected ports in the indexing disc 6 which rotates with the barrel. The indexing disc 6 rotates relative to a stationary disc 7 which is connected by stationary piping 8 to multiple process chambers 9. Fluid streams enter the rotary distribution apparatus through pipes 2 within the central core 1 and are then supplied via the rotating piping 5 to the indexing disc 6, and then via the stationary disc 7 and the stationary piping 8 to the selected process chambers 9. The fluid streams return from the process chambers and follow a similar route in reverse and are eventually discharged from the apparatus through the fixed pipes 2. Rotation of the indexing disc 6 results in the flow being directed to selected process chambers, which are in flow communication with the stationary disc.
A bearing and drive arrangement is required to maintain alignment and a sealing pressure between the indexing and stationary discs. In the standard rotary distribution arrangement design a slew ring 10 is bolted to the stationary disc and the indexing disc. The slew ring has an external gear 11 which is used to drive the unit. The use of a slew ring has the advantage that the area at the centre of the discs is left clear for the feed and product pipes to enter the central core from either or both the top or the bottom. In the standard design the barrel is mounted on top of the discs.
A consequence of this design (and the sealing system) is that pipes connecting the rotating and stationary discs have to be orientated in a vertical direction, as the slew ring prevents horizontal, side-entry of pipes into the indexing discs. In certain, typically small scale, applications it becomes advantageous to have horizontal connections into the indexing or stationary discs, due to cost, complexity and space considerations. However, the use of a slew ring bearing makes this impractical.
It is accordingly an object of the invention to provide a new rotary distribution arrangement, and in particular a drive arrangement therefor, which that will, at least partially, alleviate the above disadvantages.
It is also an object of the invention to provide a new rotary distribution arrangement and in particular a drive arrangement therefor, which will be a useful alternative to existing rotary distributions arrangements and drive arrangements.